The present invention relates to an automatic ice maker and a position control method for an ice tray in the automatic ice maker, and more particularly, to an automatic ice maker and a position control method for an ice tray in the automatic ice maker, which can automatically control a position of the ice tray at the time of recovery from power failure.
A general automatic ice maker mounted in a freezing room of a refrigerator includes an ice tray for containing water to be made into ice, a water supply unit for supplying the water to the ice tray, an ice removal motor for inverting and re-righting the ice tray, and an ice container installed beneath the ice tray, for containing the ice. In such an automatic ice maker, water is supplied to the ice tray at the state where the ice tray is in the horizontal upright position, to then perform ice making. If the ice making is completed, the ice tray is inverted by the ice removal motor, to thereby displace the ice from the ice tray to the ice container. If the ice is separated from the ice tray, the ice tray is returned to the former horizontal position for ice making, whereupon water supply and ice making operations are resumed. A level detection switch is provided to detect as to whether the ice tray remains at an ice making horizontal position. Meanwhile, a full ice detection switch is operated by a full ice detection lever to recognize whether the ice container is full of ice. If a full ice state has been recognized, ice making is stopped.
In such a conventional automatic ice maker, when a refrigerator is initially installed, or is re-activated after it has been deactivated owing to the failure of power supply, it cannot be accurately judged as to whether or not the ice tray is in a horizontal position for making ice. For example, when the power failure occurs, the ice tray may be in an inverted position for removing the ice, but the level detection switch comes to recognize that the ice tray is in an upright position. If an ice making operation is then performed, water supplied to the ice tray is not contained in the ice tray but falls into the ice container to thereby spoil already-made ice.
To accurately position an ice tray at the time of power recover, a mechanism shown in FIG. 7 is employed in the technology disclosed in Japanese patent laid-open publication No. Hei4-124570. In this known art, a first marker 120 for indicating an ice making upright position and a second marker 121 for indicating an inverted position are provided on a rotational body 119 which rotates along with an ice tray 109. These two markers 120 and 121 are formed of a different length from each other. Also, a light emitting diode (LED) 123 and a photo transistor 124 opposing the LED 123 are provided as a detection means for detecting the position of the marker 120 or 121. Based on the output signal of the photo transistor 124, a position of the ice tray 109 is judged, to place the ice tray 109 in the ice making upright position. If power is supplied at the time of power recovery, the ice tray 109 is rotated in a predetermined direction, for example, in the direction opposite to an arrow shown in FIG. 7, and at the same time a time counting operation starts. The markers 120 and 121 detected during the rotational operation are distinguished via the counted duration time, to thereby determine a position of the corresponding ice tray 109 at the time of power failure. The ice tray 109 is then returned to the former (power-recovery) position or is remains in its current state according to the determination result, to thereby cause the ice tray 109 to be in an ice making upright position.
However, in the above prior art, since it is necessary to rotate the ice tray in order to determine its position when power is resumed, a comparatively complicate determination process is needed and much time is consumed for determining the position of the ice tray and positioning the ice tray. Also, additional elements such as a LED and a photo transistor are needed.